The present invention relates to a multi-purpose transfer printing apparatus and more particularly to one which comprises an adjustable conveyor and a plurality of replaceable ink containers, silicon rubber heads and blade seats whereby the multi-purpose transfer printing apparatus can be controlled by a numerical control system to effect the multi-color printing operation for various workpieces with different sizes and shapes, such as toys, shoes, stationery etc. Conventional transfer printing apparatus can be classified into two types, single color and multi-color.
FIG. 1 shows a perspective view of a conventional single color transfer printing apparatus which comprises a table(A), an ink container(B), a brush (C) and a silicon rubber head(D). The table(A) is provided with adjustable means(X) and (Y) which are used to adjust the position of the workpiece. Behind the table(A) the ink container (B) is disposed. The desired ink and the etched plate with desired pattern can respectively be placed into the ink container(B). The brush(C) together with the silicon rubber head(D) are mounted above the ink container(B). In operation, firstly place the etched plate with desired pattern into the ink container(B) and supply the ink container(B) with the desired ink. Secondly, lower the silicon rubber head(D) to absorb the ink received in the etched portion of the etched plate and then print the desired pattern onto the workpiece. Such single color transfer printing apparatus can only effect single color printing operation.
FIG. 2 shows a perspective view of a conventional four-color transfer printing apparatus which comprises four ink containers(B), four brushes(C) and four silicon rubber heads(D) which are similar to those illustrated in FIG. 1. A race track type conveyor(E) is arranged to cooperate with said ink containers(B), brushes(C) and silicon rubber heads(D) so as to simultaneously effect the four-color printing operation. The operating procedures of the four-color transfer printing apparatus are similar to those of the single color transfer printing apparatus.
Referring to FIG. 2, the conveyor(E) is provided with a plurality of stations(F) (See FIG. 2A) on which clamping means(G) can be mounted. In operation, we have to spend much time to align each workpiece on the station(F) with each corresponding silicon rubber head(D). Further, since the pins(H), which are used to position the station(F), are easily worn out (See FIG. 2b), the positioning accuracy of the station(F) lacks reliability. In addition, the plate , the silicon rubber head and the station all are not replaceable, the flexibility of the four-color transfer printing apparatus is significantly limited.
FIG. 3 is a perspective view of a conventional three-color transfer printing apparatus of which the structure is similar to that of the four-color transfer printing apparatus except for the disc type conveyor(I).
Conclusively, the disadvantages of the conventional transfer printing apparatus are as follows:
1. The stations disposed on the race track type conveyor/disc type conveyor are too many to be easily adjusted and the pins for positioning. The stations are easily worn out so that the printing result is not reliable.
2. Conventional transfer printing apparatus, either the single color type or the multi-color type can not increase the number of colors or replace the existing colors. Therefore the function of such apparatus is significantly limited.
3. Since the ink container, the silicon rubber head and the station of the conveyor of the conventional transfer printing apparatus all are fixed, the workpieces with different sizes and shapes can not be printed by a single apparatus.
4. Conventional transfer printing apparatus see the circuit board associated with a plurality of micro switches to continuously control the printing operation. However, such micro switch may easily cause poor contact or unexpected interrupt/disturbance so that the workpiece to be printed or silicon rubber head or brush will easily be destroyed.